Cold-brew coffee is coffee brewed using cooler water to extract flavors from coffee grounds, compared to hot water extraction methods in which the coffee flavors are with extracted very hot water that may be near or even above the boiling temperature of the water. Such hot water-extracted coffee includes, for example coffee prepared by steeping with hot water in a French press, percolated coffee, hot-drip coffee and espresso. Cold-brew coffee is often made from water either at ambient room temperature or water that has been chilled, for example by adding ice to the water or refrigerating the water prior to the brewing operation. Because of the lower water temperature, there may be a significantly different mixture of components extracted from the coffee grounds during the brewing process than for hot water extraction brewing methods, and as a result cold-brew coffee may have a significantly different flavor and feel.
Hot brewing cycles for preparing hot water-extracted coffee tend to be relatively short, on the order of several minutes for hot-drip coffee and even shorter for espresso. As a result in commercial coffee establishments such as coffee shops and restaurants, hot water-extracted coffee is normally made as needed during the business day largely in response to customer demand. In contrast, cold-brewing cycles tend to be quite long, often on the order of 8 hours or more, and require significantly more planning and lead-time for such a commercial coffee establishment.
One type of brewing technique for cold-brewing coffee involves steeping the coffee grounds in a bath of the cool water for many hours, followed by separation of the cold-brew coffee from the used coffee grounds using a screen or filter. Such a cold-steeping technique may be performed for example in a French press-type system or in a so-called “Toddy” system. Another type of brewing technique for cold-brewing coffee involves dripping the cool water over a bed of coffee grounds for several hours and collecting the cold-brew coffee exiting the coffee grounds over that long brewing cycle. Such a slow-drip technique is sometimes referred to as a Kyoto-style brewing technique. Both of these types of techniques may be used to prepare high-quality cold-brew coffee, although the brewing systems in both cases tend to be of limited size designed to brew only small quantities of cold-brew coffee. Commercial establishments therefore may need to operate several of these brewing systems to produce larger quantities of cold-brew coffee. With respect to the cold-steep brewing technique, the cold-steep brewing systems tend to be relatively convenient to use and relatively easy to clean in preparation for the next cold-brewing cycle. However one problem with such cold-steep brewing systems is that a significant amount of the coffee brewing potential of the coffee grounds may be effectively lost due to residual cold-brew coffee that remains with the used coffee grounds. With respect to cold-drip brewing methods, the cold-drip brewing systems tend to be cumbersome and not easy to use and not easy to clean in preparation for the next brewing cycle.